[solved] I get some QGLWidget + OpenGLES 2.0 problems

Tratstil

I try to use QGLWidget and OpenGLES 2.0 to write a game, my problem is the game always render the (0,0) coordinate in center of screen instead of top left corner. The code like this
@QGraphicsScene scene;
scene.setSceneRect(QRect(0,0,SCREEN_WIDTH,SCREEN_HEIGHT));
GraphicsView viewer(&scene;);
_qtgame._glwidget->resize(SCREEN_WIDTH,SCREEN_HEIGHT);
_qtgame._glwidget->rect().topLeft();
viewer.setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
viewer.setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
viewer.setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
viewer.setFrameStyle(0);
viewer.setViewport(_qtgame._glwidget);
viewer.showFullScreen();@

and
@
void GLWidget::resizeGL(int width, int height){
glViewport(0, 0, DEVICE_WIDTH, DEVICE_HEIGHT);
}@

Did I forget some things?

ZapB

Just do this:

@
viewer.setViewport(new QGLWidget)
@

there is no need to sub-class QGLWidget and reimplement resizeGL().

Tratstil

Thanks ZapB for help. But I need overwritten QGLWidget to make GLSL programe, I try no reimplement resizeGL() and rewrite my code as follow, but the (0,0) still stay at center of screen. Maybe I do something wrong here, but I don't know.

@int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QApplication::setGraphicsSystem("opengl");
QtGame _qtgame;
_qtgame._viewer->showFullScreen();//now i handle the viewer inside _qtgame.

QTimer *timer = new QTimer(&#41;;
timer->setInterval(500&#41;;
QObject::connect(timer, SIGNAL(timeout()), &_qtgame, SLOT(ProcessSignal()));
timer->start();
return app.exec&#40;&#41;;

}
@

QtGame show like this
@
//_viewer and _glwidget are public.
QtGame::QtGame(){
QGraphicsScene scene;
scene.setSceneRect(QRect(0,0,k_SCREEN_WIDTH,k_SCREEN_HEIGHT));
_viewer = new GraphicsView(&scene;);
_viewer->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
_viewer->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
_viewer->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
_viewer->setFrameStyle(0);
_viewer->setViewport(new GLWidget());
_glwidget = (GLWidget*)_viewer->viewport();
}
void QtGame::ProcessSignal(){
_glwidget->updateGL();
_glwidget->paintGL2();
}
@

and the GLWidget: public QGLWidget

@
void GLWidget::initializeGL ()
{
//makeCurrent();
ConfigOpenGL();// I create my GLSL programe here.
glClearColor(1.0f, 0.972f, 0.862f, 1.0f);
glViewport(0, 0, k_DEVICE_WIDTH, k_DEVICE_HEIGHT);
}
void GLWidget::paintGL2(){
swapBuffers();
makeCurrent();
glViewport(0, 0, k_DEVICE_WIDTH, k_DEVICE_HEIGHT);
glClearColor(0.989f, 0.989f, 0.872f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
Draw();//and draw the regtangle (0.0f, 0.0f , 0.9f, 0.9f) here
}
@
And result
!http://files.myopera.com/tratstil/files/20110728-181150.png(Screen shot)!

Tratstil

After read the opengl_es2 exsample, i know that by default the (0,0) coordinate (in my case) is center of screen.

and i do this to move the (0,0) coordinate to top-left corner. I multiply vertex with a (4x4) matrix.

@
_projectionMatrix.Identity();
_projectionMatrix.Ortho(-(float)k_SCREEN_WIDTH,+0.0f,+0.0f,-(float)k_SCREEN_HEIGHT,-1.0f,+1.0f);
@
the code to Identity and Ortho can be found "here ":http://db-in.com/blog/2011/04/cameras-on-opengl-es-2-x/

Thanks everybody!
p/s : My english is very limited to representing my idear :D